The present invention relates to a process for the production of perfuming compositions, to perfumed products, and to products so obtained.
In particular, the present invention envisages their use in the perfumery field. The compounds exhibit very interesting olfactory properties and can be used, inter alia, to prepare perfuming compositions and perfumed products.
The perfumery industry is constantly seeking products which by their originality, volume and the strength of their fragrance can endow compositions containing them with a unique character.
We have now discovered that alkylsalicylic acid esters as defined below, in particular methylsalicylic acid esters, exhibit novel olfactory properties.
It should be noted that it is impossible for the skilled person to predict whether a given chemical compound will or will not have an interesting scent from the olfactory viewpoint which could be used in the perfumery field.
More specifically, the present invention concerns a process for the production of perfuming compositions, perfumed products and substances for perfumery characterized in that an effective quantity of an alkylsalicylic acid ester is added to the usual constituents of these compositions, substances and finished products.
The present invention also concerns perfuming compositions, perfumed substances and products characterized in that they comprise, as an active ingredient having an influence on the scent, an effective quantity of an alkylsalicylic acid ester.
The invention thus resides in a novel use of esters of an alkylsalicylic acid as a perfuming ingredient.
The invention also relates to certain alkylsalicylic acid esters as novel products.
The perfuming ingredient of the invention is an alkylsalicylic acid ester. More particularly, it has the following general formula (I): 
in which formula (I):
n is a number equal to 1 or 2.
R1 represents a hydrocarbon radical which may or may not be substituted, containing 1 to 40 carbon atoms, more particularly a linear or branched, saturated or unsaturated, aliphatic, acyclic radical, or a saturated or unsaturated, monocyclic or polycyclic, carbocyclic or heterocyclic radical;
R2 represents an aliphatic radical, preferably saturated, preferably less than 4.
More particularly, the alkylsalicylic acid esters have formula (I) in which the different radicals R1 and R2 have the following meaning.
The number of carbon atoms in R1 is generally between 1 and 40 carbon atoms, preferably between 1 and 12 carbon atoms.
Radical R1 can be a monovalent radical which may or may not be substituted, which may be a linear or branched, saturated or unsaturated, aliphatic acyclic radical; or a saturated or unsaturated, monocyclic or polycyclic, carbocyclic or heterocyclic radical.
Radical R1 is a linear or branched, saturated or unsaturated, aliphatic acyclic radical.
More precisely, R1 is a linear or branched alkyl, alkenyl or alkadienyl radical preferably containing 1 to 40 carbon atoms.
The hydrocarbon chain can optionally be interrupted by a heteroatom (for example oxygen or sulphur) or by one of the following groups: xe2x80x94COxe2x80x94, xe2x80x94COOxe2x80x94, and/or can carry one of the following substituents: xe2x80x94OH, xe2x80x94COOR3, xe2x80x94, xe2x80x94CF3: in these formulae, R3 preferably represents hydrogen or a linear or branched alkyl radical containing 1 to 4 carbon atoms, more particularly a methyl or ethyl radical.
R1 can represent a carbocyclic monocyclic radical. The number of carbon atoms in the cycle can vary from 3 to 8 carbon atoms, but is preferably 5 or 6 carbon atoms.
The carbocycle can be saturated or can contain 1 or 2 unsaturated bonds in the cycle, preferably 1 or 2 double bonds.
Examples of carbocycles area cycloalkoyl or cycloalkenyl radical containing 3 to 8 carbon atoms, preferably a cyclohexyl, cyclohexen-yl or cyclohepten-yl radical.
When R1 represents a saturated or unsaturated carbocyclic monocyclic radical, it is possible for one or more carbon atoms of the cycle to be replaced by one or more heteroatoms, preferably oxygen, nitrogen or sulphur or by a functional group, preferably a carbonyl or ester group, resulting in a heterocyclic monocyclic compound. The number of atoms in the cycle can vary from 3 to 8 atoms but is preferably 5 or 6 atoms.
Radical R1 can also be carbocyclic and polycyclic, preferably bicyclic which means that at least two cycles have two carbon atoms in common. For polycyclic radicals, the number of carbon atoms in each cycle is between 3 and 6: the total number of carbon atoms is preferably 7.
Examples of currently encountered bicyclic structures are given below: 
Radical R1 can also be heterocyclic and polycyclic, preferably bicyclic, meaning that at least two cycles have two atoms in common. In this case, the number of atoms in each cycle is between 3 and 6, more preferably 5 or 6.
Radical R1 can represent a linear or branched, saturated or unsaturated aliphatic radical carrying a cyclic substituent. Examples of cyclic substituents are cycloaliphatic, aromatic or heterocyclic substituents, in particular cycloaliphatic compounds containing 6 carbon atoms in the cycle, or benzene rings. More particular examples are arylalkyl radicals containing 6 to 12 carbon atoms, preferably the benzyl radical.
It should be noted that if radical R1 contains a cycle, it is possible for the cycle to carry a substituent of any type. The substituents usually carried by the cycle are one or more alkyl or alkoxy radicals preferably containing 1 to 4 carbon atoms, preferably three methyl radicals, a methylene radical (corresponding to an exocyclic bond), an alkenyl radical, preferably an isopropen-yl radical, or a halogen atom, preferably chlorine or bromine.
More preferably, the alkylsalicylic acid esters have the following general formula (Ia): 
in which formula (Ia):
n is a number equal to 1 or 2;
R1 represents a linear or branched alkyl radical containing 1 to 12 carbon atoms, preferably 1 to 8: or a cycloalkyl radical preferably containing 6 carbon atoms, or an aralkyl radical containing 6 to 12 carbon atoms, preferably 7 or 8 carbon atoms;
R2 represents a linear or branched alkyl radical containing 1 to 4 carbon atoms, preferably 1 or 2.
Of compounds with formula (I), those in which radical R1 contains more than two carbon atoms are novel products and are claimed as such.
Preferred compounds are those with formula (Ia) in which R1 represents an alkyl radical such as methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl, isoamyl, n-hexyl, 2-ethylhexyl; a cyclohexyl radical; or a benzyl radical or a xcex2-phenylethyl radical, and R2 represents a methyl or ethyl radical.
Specific examples of alkylsalicylic acid esters with formula (I) are, among others:
methyl 2-hydroxy-3-methyl-benzoate;
ethyl 2-hydroxy-3-methyl-benzoate;
isopropyl 2-hydroxy-3-methyl-benzoate;
n-propyl 2-hydroxy-3-methyl-benzoate;
n-butyl 2-hydroxy-3-methyl-benzoate;
isobutyl 2-hydroxy-3-methyl-benzoate;
amyl 2-hydroxy-3-methyl-benzoate;
isoamyl 2-hydroxy-3-methyl-benzoate;
n-hexyl 2-hydroxy-3-methyl-benzoate;
2-ethylhexyl 2-hydroxy -3-methyl-benzoate;
cyclohexyl 2-hydroxy-3-methyl-benzoate;
benzyl 2-hydroxy-3-methyl-benzoate;
xcex2-phenylethyl 2-hydroxy-3-methyl-benzoate;
methyl 2-hydroxy-4-methyl-benzoate;
ethyl 2-hydroxy-4-methyl-benzoate;
isopropyl 2-hydroxy-4-methyl-benzoate;
n-propyl 2-hydroxy-4-methyl-benzoate;
n-butyl 2-hydroxy-4-methyl-benzoate;
isobutyl 2-hydroxy-4-methyl-benzoate;
amyl 2-hydroxy-4-methyl-benzoate;
isoamyl 2-hydroxy-4-methyl-benzoate;
n-hexyl 2-hydroxy-4-methyl-benzoate;
2-ethylhexyl 2-hydroxy-4-methyl-benzoate;
cyclohexyl 2-hydroxy-4-methyl-benzoate;
benzyl 2-hydroxy-4-methyl-benzoate;
xcex2-phenylethyl 2-hydroxy-4-methyl-benzoate;
methyl 2-hydroxy-5-methyl-benzoate;
ethyl 2-hydroxy-5-methyl-benzoate;
isopropyl 2-hydroxy-5-methyl-benzoate;
n-propyl 2-hydroxy-5-methyl-benzoate;
n-butyl 2-hydroxy-5-methyl-benzoate;
isobutyl 2-hydroxy-5-methyl-benzoate;
amyl 2-hydroxy-5-methyl-benzoate;
isoamyl 2-hydroxy-5-methyl-benzoate;
n-hexyl 2-hydroxy-5-methyl-benzoate;
2-ethylhexyl 2-hydroxy-5-methyl-benzoate;
cyclohexyl 2-hydroxy-5-methyl-benzoate:
benzyl 2-hydroxy-5-methyl-benzoate;
xcex2-phenylethyl 2-hydroxy-5-methyl-benzoate
Compounds with formula (I) give off a very interesting scent.
These products can be used as perfuming ingredients in perfuming compositions, substances and perfumed products.
The term xe2x80x9cperfuming compositionsxe2x80x9d means mixtures of various ingredients such as solvents, solid or liquid supports, fixatives, various scenting compounds, into which alkylsalicylic acid esters preferably with formula (I) are incorporated, which are used to produce a variety of types of finished products, with the desired fragrance.
Perfume bases constitute preferred examples of perfuming compositions in which the alkylsalicylic acid esters preferably with formula (I) can advantageously be used.
Eau de toilette, after-shave lotion, perfume, soap, bath or shower gel or deodorant or antiperspirant in the form of sticks or lotions constitute examples of finished products or substances which the alkylsalicylic acid esters preferably with formula (I) endow with their original note.
They can also be used in all types of shampoos and hair-care products.
They can also perfume all types of talcs or powders.
They can also be used in room sprays or any cleaning product.
A further example of compositions in which the compounds can advantageously be used is represented by the usual detergent compositions. Such compositions generally comprise one or more of the following ingredients: anionic, cationic or amphoteric surfactants, bleaching agents, optical brighteners, various fillers, and anti-redepositing agents. The nature of these various components is not critical and the alkylsalicylic acid esters, preferably with formula (I) can be added to any type of detergent composition. They can be introduced into fabric softeners, in liquid form or into compositions deposited on a support, usually a non-woven support, for use in clothes dryers.
The amount of the compositions of the invention of alkylsalicylic acid ester, preferably with formula (I), expressed as the percentage by weight in the composition under consideration, depends on the nature of the composition (a base for a perfume or eau de toilette, for example) and the strength and nature of the desired influence in the finished product. It is clear that in a perfume base the quantity of alkylsalicylic acid ester preferably with formula (I) can be very high, for example over 50% by weight, and can attain 90% by weight while in a perfume, an eau de toilette or an after-shave lotion, this quantity can be below 50% by weight.
In detergent compositions, in particular for domestic use, and in soaps, the quantity of alkylsalicylic acid ester can be of the order of 1% to 2%.
It can also be used in perfumed shampoos in an amount of 0.5% to 2%, or to perfume any hair product.
Thus the lower limit of the amount of alkylsalicylic ester preferably with formula (I) can be that which causes a perceptible modification in the scent or fragrance or the note of the finished product. In some cases, this minimum amount can be of the order of 0.01% by weight. Clearly, quantities which are not included in the limits indicated above can be employed without departing from the scope of the invention.
One route to alkylsalicylic esters consists of reacting an alkylsalicylic acid and an alcohol in the presence of an acid catalyst.
More particularly, the following are reacted:
an alkylsalicylic acid with formula (II): 
xe2x80x83where R2 and nitrogen have the meanings given above,
an alcohol with formula (III):
R1xe2x80x94OHxe2x80x83xe2x80x83(III)
xe2x80x83where R1 has the meaning given above.
Particular examples of compounds with formula (II) are 2-hydroxy-3-methyl-benzoic acid, 2-hydroxy-4-methyl-benzoic acid, and 2-hydroxy-5-methyl-benzoic acid.
Preferred examples of alcohols with formula (III) are primary or secondary alcohols containing 1 to 12 carbon atoms, preferably methanol, ethanol, cyclohexanol, benzyl alcohol, and xcex2-phenylethyl alcohol.
In the process of the invention, the acid is reacted with an alcohol with formula (III).
Compounds with formula (II) are commercially available.
A number of preparation modes can be envisaged.
A first variation consists of reacting an alkylsalicylic acid with an alcohol with formula (III).
It is also possible to carry out esterification in the presence of an organic solvent. The organic solvent is selected so that it forms an azeotrope with water and the boiling point of the azeotrope with water is lower than that of the alcohol used. Examples of solvents are toluene, cumene and pseudocumene.
It is preferable to use a direct esterification process carried out in the absence of an organic solvent for alcohols containing 1 to 5 carbon atoms.
In the case of heavy alcohols containing more than 5 carbon atoms, it is preferable to carry out the reaction in the presence of an organic solvent
The different reactions are carried out in the presence of a conventional acid type catalyst. Particular examples are sulphuric acid, hydrochloric acid, p-toluene sulphonic acid, alkoyl titanates, preferably isopropyl or n-butyl titanates, and antimony oxide.
The quantity of reactants present is determined so that the alcohol with formula (III) is generally in excess with respect to the alkylsalicylic acid. The excess varies widely, preferably from 50% to 3000% with respect to the stoichiometric quantity. More preferably, it is selected to be between 100% and 2000% of the stoichiometric quantity.
The quantity of catalyst used, expressed with respect to the weight of alkylsalicylic acid, is advantageously between 1% and 30%.
When an organic solvent is present, the quantity used can vary widely. As an indication, the quantity of organic solvent can represent 50% to 1000% of the weight of the alkylsalicylic acid used.
The reaction temperature is selected so that it is sufficient to allow the reaction to occur.
The reaction temperature is preferably 50xc2x0 C. to 150xc2x0 C.
The reaction is advantageously carried out at atmospheric pressure.
The reaction is preferably carried out in an inert gas atmosphere which can be nitrogen or a rare gas, preferably argon.
From a practical viewpoint, the process of the invention is simple to carry out.
The different reactants can be introduced in any order. The order of introducing the reactants is preferably as follows: the alkylsalicylic acid and alcohol with formula (III) are introduced, then the acid catalyst.
The reaction medium is heated to the desired temperature, while stirring the reaction medium.
During the reaction, water forms in the reaction medium. In a preferred variation of the invention, the water is eliminated from the reaction medium as it is formed using any known means, in particular azeotropic distillation.
At the end of the reaction, the desired alkylsalicylic acid ester is obtained, along with excess alcohol with formula (III) and the catalyst.
The alkylsalicylic acid ester can be recovered from the reaction medium using any suitable means.
Thus it can be washed with water followed by neutralisation with a base.
The quantity of base, preferably sodium hydroxide, carbonate or bicarbonate, is such that the pH is in the range 6 to 8.
The organic phase is separated out and fractionated by distillation. Usually, the excess alcohol with formula (III) is recovered first then the alkylsalicylic acid ester, preferably with formula (I).